Readily removable shaft cam construction



May 14, 1957 J. c. DANLY 2,792,459

READILY REMOVABLE SHAFT CAM CONSTRUCTION v INVENTOR g y JAMES C. DHA/Y BY Y A ORNEY 2 Sheets-Sheet 2 J. C. DANLY 'READILY REMOVABLE SHAFT CAM CONSTRUCTION May 14, 1957 Filed April 21, 1955 INVENTOR Ms C. DHA/y A ORNEY iinited States A Patent i O READILY REMOVABLE SHAFT CAM CONSTRUCTION laines C. Danly, River Forest, lll., assigner te Dainty Machine Specialties, Inc., Chicago, il., a corporation of Illinois Application April 21, 1955, Serial No. 562,945

12 Claims. (Cl. 200-5) My invention relates to a readily removable shaft cam construction and more particularly to a readily removable shaft cam construction which permits rapid and expeditious removal of cams from and replacement of cams on a shaft.

The copending application of Philo H. Danly et al., Serial No. 365,l07, filed l une 30, 1953, now Patent No, 2,- 753,405, issued July 3, 1956, discloses a rotary limit switch assembly for use with a power press to control the points in the press cycle at which various operations take place. Some of the automatically controlled operations are, for example, stopping the press at the top of the strolte, the operation of mechanical handling devices, initiation of the feeding and removal of material, the operation of die stops, the supplying of drawing compound to the stock, and the operation of the locking device for the press cushion. rhe switch disclosed in the copending application includes a plurality of radially spaced cams clamped to a shaft driven from the main press drive. rihe relative angular disposition of the cams on the shaft is such that the various operations to be controlled are performed in the proper timed sequence.

In order to change the character of the operation performed by the press, it is necessary to remove some of the switch cams from the limit switch assembly shaft and replace them with cams having longer or shorter arcs of engagement with the limit switch cam follower rollers. The relative angular positions of the cams in the switch disclosed in the copending application may easily be ad justed. In order to replace a cam in the switch, however, the switch cam mounting means must be disassembled.

I have invented a readily removable shaft cam construction which provides for rapid and expeditious removal of a cam from and replacement of a cam on a shaft. Removal and replacement of cams carried by a shaft may be accomplished with my construction without the necessity of disassembling the shaft cam mounting means. While my construction is of general application, it is particularly advantageous when used with a rotary limit switch assembly similar to that disclosed in the said copending application.

One object of my invention is to provide a readily removable shaft cam construction which permits a rapid and expeditious removal of a cam from its shaft.

Another object of my invention is to provide a readily removable shaft cam construction which permits the rapid and expeditious replacement of cams on a cam shaft.

A further object of my invention is to provide a readily removable shaft cam construction for use with a rotary limit switch assembly.

Still another object of my invention is to provide a readily removable shaft cam construction which permits rapid and expeditious adjustment of the relative angular positions of the cams carried by the shaft.

Other and further objects of my invention will appear from the following description.

ln general, my invention contemplates the provision of a. shaft and means for removably mounting a plurality of cams on the shaft. l provide clamping means for clamping the cams in predetermined angular relationship to the shaft for rotation with it. Resilient means retains the cams on the shaft while it permits radial movement of the cams with respect to the shaft when the clamping means is released a predetermined amount. My cams are so constructed that they may readily be removed from the shaft and replaced upon release of the clamping means.

In the accompanying drawings which form part of the instant specification and which are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views:

Figure l is a longitudinal sectional view of a rotary limit switch assembly including my readily removable shaft cam construction.

Figure 2 is a sectional view of my readily removable shaft cam construction taken along the line 2-2 of Figure l.

Figure 3 is a fragmentary sectional view drawn on au enlarged scale of my readily removable shaft cam construction.

Figure 4 is an exploded view of my readily removable shaft cam construction showing one of the cams and its associated mounting means.

More particularly, referring now to Figures l and 2 of the drawings, the rotary limit switch assembly with which my readily removable shaft cam construction may be used includes a housing, indicated generally by the reference character 10, having a back 12, a top 14, a bottom 16 and respective sides 1S and 2i). The front of the housing itl is open to provide access to the operating parts of the switch assembly. lt may, if desired, be closed by a removable cover (not shown). A bearing bushing 22, carried by a support 24 on side 20, and a ball bearing 26 rotatably mount a switch assembly drive shaft 2S within housing 10. A bearing housing 30 disposed in an opening 32 in side 18 houses bearing 26. Screws 34 se` cure the housing to side 18. I dispose a shock absorbing washer 36 between housing 3? and side 18. An annular plate 3S secured to housing 3G by screws 4t) retains bearing 26 within the housing 30.

The end of shaft 28 adjacent the bearing bushing 22 carries a sleeve or collar 42 retained in fixed position on A the shaft by a tapered pin 44 passing through the shaft.

As can best be seen by reference to Figures l, 3 and 4, I form shaft 28 with a boss 46 which rotatably carries a plurality of spacers 48. The switch assembly which employs my shaft cam construction includes a number of switch actuating cams 50 or 52. As can be Seen by reference to Figure 2, cams Sii may, for example, be thirty degree cams which engage the switch cam followers to be described hereinafter for thirty degrees of arc, while cams 52 engage t e switch actuating rollers for greater or less degrees of arc. For example, they may engage their rollers for one hundred and twenty degrees.

As can best be seen by reference to Figure 4, l form each of the cams Sil and 52 with a slot 54 which is open at one end and closed at the other end to form a bearing surface S6 which rests on the boss 45 of shaft 28. It will be seen that a cam 50 or cam S2 may be slipped over the boss 136 owing to its slot 54 so that surface 56 engages boss 46. Each of the spacers 4S is formed with a key 58 for engaging the slot 54 of a cam :39 or cam S2 to provide a driving connection between the spacer and the cam. An annular boss 60 on the face of each spacer 48 exerts a clamping pressure on an annular recess 62 on the associated cam 50 or cam 52 to clamp the cam to the shaft in a manner to be described hereinafter.

Referring now to Figures l and 3, i form each of a plurality of switch supporting arm mounting spacers 63 with a hub 70 which rotatably mounts a limit switch supporting arm 72. A plurality of keys 6d in hubs 70 ride in a keyway 66 formed in boss 46 to mount the respective switch supporting arm mounting spacers 6d on boss 46 for rotationwith it and for axial movement along it. One spacer 68 is provided for each spacer 48 and associated cam 50 or cam 52. Washers 74 separate respective switch mounting arms 72 from adjacent cam Si? or cam 52. The order of parts on boss 46, as viewed from right to left in Figure 1, is a spacer 48, a cam 5t) or cam 52, a washer 74 and a switch mounting arm 72 on hub 70 of a spacer 68. Adjacent the left end of boss 46, as viewed in Figure 1, past the last spacer d, i mount an end spacer 76.

in order to clamp the assembled parts on boss 46 for rotation with shaft 28, I thread a recessed nut 73 on a threaded portion'ii of shaft 2S. A spring 82 disposed within the recess 34 of nut 7S bears against a washer 36 carried by boss 46 between spacer. 76 and the nut 73. A hole 86 in nut 78 provides a means by which nut 7i; may be turned with a Spanner wrench, or the like.

Each of the cams Si) or 52 is arranged to engage a cam roller 9d carried by a pin 92 on one end of a limit switch actuating arm 94. A nut 96, or the like, fixes the other end of arm 94 on the shaft 9S of a limit switch, indicated generally by the reference character ldd. Each of the shafts 9S may conveniently be rotatably mounted by a respective bushing (not shown) in one of the switch supporting arms 72. Respective slots 162 in top llland bottom 16 of housing 10 adjustably mount respective locking assemblies, indicated generally by reference character 104. Each of the assemblies ldd provides a means for adjusting the angular position on shaft 2S of a switch arm 72 carrying a limit switch 10i?. The details of construction and operation of the locking assemblies 104 are described in the said copending application. Conductors 105 provide electrical connections for switches 100.

Nut 78 provides a means for clamping the cams in predetermined angular positions on boss 46 for rotation with shaft 28. As nut 7S turns in a clockwise direction, as viewed from the left end of shaft 23 in Figure 1, the nut exerts a pressure to clamp spacer 76 and spacers 48 and 68, as well as washers 7-, against sleeve 42. As a result of this action, a cam 59 or cam 52 is clamped between a washer 74 and the boss 60 of a spacer 48. Hubs 76 of spacers 6@ transmit the clamping pressure to washers 711i without immobilizing the switch mounting arms 72. In other words, when cams 5t) or 52 are clamped to boss t6 for rotation with shaft 2S, arms 72 are not clamped and hubs 7) may rotate with respect to the arms.

VSpring 82 retains cams 5i) and S2 on boss 46 while permitting adjustment of the angular positions of the cams when nut 78 is backed oif a predetermined distance. When the nut is so backed off, it relieves the clamping pressure exerted by the nut itself. The pressure exerted by spring 82 is such that the angular position of any one of the cams 50 or 52 may be changed. When the nut 78 is backed off a sufficient distance, any one of the cams 50 or 52 may be slipped off the shaft and a new cam may be slipped on the shaft to replace the removed cam. As the replacing cam is slipped on the shaft, its slots 54 engages the key 5S of the spacer i5 associated with the removed cam. its angular position may then be adjusted as desired.

As can be seen by reference to Figure 4, each of the spacers 48 is provided with a scale 106 around its periphery. Each of the spacers 68 has an indicating groove 108. When the angular position of a cam 50 or 52 is adjusted, it carries the associated spacer 48 by reason of its engagement with key 58. As the cam is moved about the shaft 28, spacer 63 remains in its initial position. The cam is moved until a calibration mark corresponding to the desired angular position of the cam registers with grooveV 108.

In use of a switch assembly employing my readily removable shaft cam construction, cams 5t) and 52 are slipped onto boss 46 of shaft 28 between washers 74 and spacers 48 with their respective slots 54 engaging keys S8 of spacers 48. After the cams have been placed on the shaft, nut 7S is tightened until spring $2 exerts sufticient pressure to retain the cams on the shaft while permitting them to be rotated about the shaft. Each of the cams 50 or 52 is their positioned at the desired predetermined angular position by moving the cam and its associatedspacer 48 until a calibration mark of scale i236 corresponding to the desired position registers with groove iti-S in the corresponding spacer 68. When all cams have been moved to their proper positions nut 78 is tightened until it exerts a suihcient pressure securely to clamp the cams to boss 46 for rotation with it. As 4is pointed out hereinabove, hubs transmit this clamping pressure to the cams while permitting relative rotation between boss 46 and switch mounting arms 72. The positions of arms 72 and the switches carried thereby may be adjusted with respect to housing 1t) by the locking means 104 in a manner `described in the said copending application.

It may become necessary to replace one of the cams 5G or 52 with a cam having a different arc of contact with a limit switch cam follower roller 90. To accomplish this, nut 78 is backed off until the cam may easily be slipped o the shaft. The replacing cam is slipped onto the shaft with its slot 54 engaging the key 58 of the spacer 4S associated with the removed cam. Nut 78 is then tightened an amount sucient to retain the cam on the shaft while permitting its movement about boss 46 of shaft Z8. The Ycam is then moved to its proper predetermined angular position and nut 78 is tightened to clamp all the cams to the shaft.

It will be seen that I have accomplished the objects of my invention. I have provided a readily removable shaft cam construction which permits rapid and expeditious removal of cams from a shaft. My construction permits quick and easy replacement of cams on a shaft. While my construction is particularly advantageous when used with a rotary limit switch assembly, it is of general application and may be employed in any application where cams are to be mounted on a shaft.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of my claims. It is further obvious that various changes may be made in details within the scope of my claims without eparting from the spirit of my invention. 1t is therefore to be understood that my invention is not to be limited to the specific details shown and described.

Having thus described my invention, what l claim is:

l. A readily removable shaft cam construction including in combination a shaft, a cam formed with a slot having an open end and a closed end, said slot permitting said shaft rotatably to mount said cam, a key adapted to engage said slot, means rotatably mounting said key on said shaft and means for releasably clamping said key mounting means and said cam to said shaft.

2. A readily removable shaft cam construction including in combination a shaft, a cam formed with a slot having an open end and a closed end, said slot permitting said shaft rotatably to mount said cam, a first spacer rotatably mounted on said shaft, a key carried by said rst spacer for engaging the cam slot, and means for clamping said cam and said first spacer to said shaft for rotation therewith.

3. A readily removable shaft cam construction'including in combination a shaft, a cam formed with a slot having an open end and a closed end, said slot permitting said shaft rotatably to mount said cam, a first spacer rotatably mounted on said shaft, a key on said first spacer, said key engaging the cam slot, a switch supporting arm mounting spacer, means mounting said switch supporting arm mountingspacer on said shaft for rotation therewith and for axial movement therealong, and means for clamping said cam and said first spacer and said switch supporting arm mounting spacer to said shaft for rotation therewith.

4. A readily removable shaft cam construction as in claim 3 in which said clamping means is releasable and resilient means for retaining said cam on said shaft while permitting adjustment of its angular position on the shaft when said clamping means is released a predetermined amount.

5. A readily removable shaft cam construction as in claim 3 including a graduated scale on said first spacer and an indicating groove, said switch supporting arm mounting spacer being formed to cooperate with said scale to indicate the angular position of said cam on said shaft.

6. A readily removable shaft cam construction including in combination a shaft, a plurality of cams each formed with a slot having an open end and a closed end, said slots permitting said shaft rotatably to mount said cams, a plurality of first spacers rotatably mounted on the shaft, each of said spacers being associated with a respective cam, a plurality of keys on said first spacers for engaging the slots of respective cams, and means for reieasably clamping said cams and said first spacers to said shaft for rotation therewith.

7. A readily removable shaft cam construction including in combination a shaft, a plurality of cams each formed with a slot having an open end and a closed end, said slots permitting said shaft rotatably to mount said cams, a plurality of iirst spacers rotatably mounted on the shaft, each of said spacers being associated with a respective cam, a plurality of keys on said first spacers for engaging the slots of respective cams, a plurality of switch supporting arm mounting spacers, means mounting said switch supporting arm mounting spacers on said shaft for rotation therewith and for axial movement therealong, said switch supporting arm mounting spacers being disposed on said shaft adjacent respective first spacers, and means for releasably clamping said cams and said first spacers and said switch supporting arm mounting spacers on said shaft for rotation therewith.

8. A readily removable shaft cam construction as in claim 7 in which said switch supporting arm mounting spacers are formed with hubs, a plurality of switch sup- 6 porting arms respectively mounted on said hubs, said hubs permitting relative rotation between said arms and said shaft when said clamping means clamps said cams and said first spacers and said switch supporting arm mounting spacers to said shaft.

9. A readily removable shaft cam construction as in claim 7 including resilient means for retaining said cams on said shaft while permitting movement of said cams about said shaft when said clamping means is released a predetermined amount.

10. A readily removable shaft cam construction as in claim 7 including respective graduated scales on said rst spacers, each of said switch supporting arm mounting spacers being formed to cooperate with a respective scale to indicate the angular position of the associated cam on said shaft.

11. A readily removable shaft cam construction iucluding in combination a shaft, a cam formed with a slot having an open end and a closed end, said slot permitting said shaft rotatably to mount said cam, a first spacer rotatably mounted on said shaft, a key carried by said first spacer for engaging the cam slot, means for clamping said cam and said first spacer to said shaft for rotation therewith, a switch, and means mounting said switch in cooperative relationship with said cam.

12. A readily removable shaft cam construction including in combination a shaft, a plurality of cams each formed with a slot having an open end and a closed end, said slots permitting said shaft rotatably to mount said cams, a plurality of spacers rotatably mounted on the shaft, each of said spacers being associated with a respective cam, a plurality of keys on said spacers for engaging the slots of respective cams, means for releasably clamping said cams and said spacers to said shaft for rotation therewith, a plurality of switches, and means mounting said switches in cooperative relationship with respective ones of said cams.

References Cited in the tile of this patent UNITED STATES PATENTS 2,169,039 Defandorf et al, Aug. 8, 1939 2,182,715 Yeske Dec. 5, 1939 2,319,701 Miller May 18, 1943 2,468,974 Hammer May 3, 1949 2,489,444 Bechler Nov. 29, 1949 2,651,698 Gracey Sept. 8, 1953 

